Biostatistics - Likelihood Ratio and Post-test Probability

Before using a diagnostic test, a person's probability of having a certain disease is defined as pre-test probability. Get your test done on the patient, and this will change to post-test probability, with the help of likelihood ratio. So what is it, and what is the difference between post-test odds and probability? All are explained in this video, enjoy!
Contents:
0:16 - Likelihood ratio definition
1:23 - Formula of likelihood ratio
1:59 - Probability vs Odds
3:25 - Odds to probability conversion
3:50 - Solved example
7:30 - Likelihood Nomogram
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[@logansept]

Lol I hope the odds of having blood pressure are 100%

[@jodiannmasigla9432]

how do i interpret a (+) and (-) likelihood ratio that both equalled to 0? is that useless? this 0 result for both was due to the test having perfect specificity value at 100% ; i would like to interpret it for an assignment

[@katielui131]

Hi, I don't understand why a perfect test would not update/improve the prior estimates but an imperfect test would?

[@uniquet_50mg]

i will soon have my parasitology exam, please make a video on helmints...

[@ATPPP]

Hello tudi,
Hopefully we will have a video about helminths in the near future

[@AbdulkarimLahmouni]

May Allah bless you

[@premkumarshrestha3368]

Helpful. thanks.

[@bilalahmad6102]

وعلیکم السلام ♥️👌

[@ranaAmeer9349]

You calculated posttest odds by multiplying pretest odds with likelihood ratio.
In First aid the formula is pretest probability times the likelihood ratio. How is that??

[@med-up-community]

In your example in your slides, the pretest probability is not for having 'Blood Pressure' per se but for Hypertension. Otherwise, your videos are top-notch. 💯💯

[@razb3129]

وعليكم السلام ورحمة الله وبركاته
Thank you so much !

[@ninaahmad1352]

Thank you so much

[@ATPPP]

You are welcome :)

[@abdulwahid-vt6pf]

Hello Sir, I'm Abdul Wahid here, I'm want to ask you, Can you please let me know how to estimate/calculate Breast Cancer Risk for the bases of patient past medical and family history? Can I calculate likelihood ratio?

[@zas881]

شُكرًا 🙏🏻

[@siddiquab.z.3476]

Waalaikumasslam

[@maryamsheikh1387]

Aoa...please cover the entire microbiology . Staphylococcus was superb.... cant find strp

[@ATPPP]

Hello Maryam,
Thank you for your comment
Don't worry, we will keep updating our microbiology list!

[@ryanhoyle5389]

This is a really nice series! The topics are really not intuitive, very difficult to teach, so I appreciate your efforts. :)

[@ATPPP]

Glad you like them!

[@shubhamkhude08]

Add video on DNA replication and GENE MUTATION please

[@ATPPP]

Hello Shubham,
Unfortunately we are not doing genetics videos, but we will take it into consideration!

[@vijaysastry4235]

Prophet Mohd bless you

[@ZaidanyZ]

Well explained thank you. I hope this series continues to help us!

[@ATPPP]

More to come!

[@alinuh5564]

MashaAllaah
Well explained JazakaAllaah

[@moazAlhamedy]

First-rate content presented in an organized way 👌 thank you

[@silence4033]

This was perfect and exactly what I was looking for.

[@ATPPP]

Perfect!

[@benghazi2012]

very poor explanation based, on crude memorization , with no logical chain of thoughts.

[@ATPPP]

Hello benghazi,
Please let us know how we can improve ;)